and Cathy Bickel
Barbering describes a nervous habit in which one gerbil chews the hair off the upper part of another gerbil's tail. Barbering rarely leads to actual injury; it is mainly a cosmetic problem.
Stress or boredom are the usual culprits. Try additional stimulation in the form of chewables, toys and out-of-cage time. If this does not help, move your gerbils to a quieter place, limit handling by children, and eliminate any possible negative interactions with other pets, such as cats stalking your gerbils.
Extreme barbering or barbering that appears on more than one gerbil in the tank, or occurring simultaneously in more than one tank, may be a sign of mites. Mites can be too small to be visible; you will need your vet to do a skin scrape and look under a microscope.